Mycotic Aortic Aneurysm and Mitral Valve Endocarditis in a Dialysis Patient with Porcelain Aorta: A Therapeutic Dilemma - A Case Report

Introduction

Mycotic aneurysms represent <1% of all aortic aneurysms but carry high mortality, particularly in immunocompromised and dialysis-dependent patients.¹ Management typically combines surgery and prolonged antibiotic therapy, but both open and endovascular approaches can be limited by hostile anatomy or persistent infection. We report a case of methicillin-sensitive Staphylococcus aureus (MSSA) mycotic aneurysm with concomitant mitral valve endocarditis in a frail hemodialysis patient, highlighting the therapeutic challenges encountered when conventional surgical or endovascular strategies are not feasible.

Case Report

A 78-year-old female with ESKD on hemodialysis, ischemic heart disease, and hypertension presented with fever, hypotension, and right-sided flank pain. She had recently returned from Malaysia, where she underwent repeated intramuscular stem cell injections for cosmetic rejuvenation. Shortly afterwards, she developed a gluteal abscess and self-administered further injections at home.

CT angiography revealed an eccentric distal thoracic aortic aneurysm with surrounding inflammatory changes, consistent with a mycotic aneurysm, on a background of severe circumferential aortic calcification (“porcelain aorta”). Blood cultures grew MSSA. Transthoracic echocardiography demonstrated a suspicious mitral lesion, and transesophageal echocardiography confirmed a 1.9 cm vegetation on the posterior mitral leaflet with mild regurgitation [Figure 1, Supplementary Figure 1 and Video 1].

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Figure 1:

(a) 3D en face view of the mitral valve showing a vegetation attached to the posterior mitral leaflet (PML, red arrow). (b) CT angiography with 3D rendering of the aorta demonstrating diffuse aortic and aortic valve calcification, coronary artery calcifications, and stents in the circumflex coronary artery. An eccentric aneurysm arising laterally from the proximal abdominal aorta is noted (red arrow). A distal aspect of a dual-lumen central venous catheter is also visible. AML: Anterior mitral leaflet; Ao: Aortic root; AA: Abdominal aorta; LAA: Left atrial appendage; PML: Posterior mitral leaflet.

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A multidisciplinary endocarditis team deemed the patient unsuitable for open repair of either the mitral valve or aneurysm due to frailty and porcelain aorta. Endovascular repair with overlapping conformable stent grafts was attempted but complicated by persistent sac filling and peri-aortic infection. Follow-up imaging showed further aneurysm enlargement and endoleak [Figure 2]. A conservative approach with intravenous antibiotics was adopted.

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Figure 2:

Endovascular aneurysm repair (EVAR): (a) Two overlapping GORE® EXCLUDER® Conformable AAA Endoprostheses w (W.L. Gore & Associates, Flagstaff, AZ, USA), measuring 23 mm ´ 4.5 cm and 26 mm ´ 4.5 mm were deployed across the aneurysm neck, with persistent aneurysm filling visible (yellow arrow). (b) CT angiography of the aorta: 48 hours post EVAR, the patent aneurysm demonstrated increased dimensions (16 ´ 12 mm) and associated active contrast extravasation (yellow arrow). Increased surrounding soft tissue stranding with hemorrhagic material.

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Discussion

Although uncommon, mycotic aneurysms carry a very poor prognosis, particularly when occurring in frail patients with multiple comorbidities. Historically, open surgical repair was the standard of care, but outcomes remain suboptimal in those with complex anatomy, such as porcelain aorta.¹

Endovascular repair is a less invasive option, with early series demonstrating feasibility as either a bridging or definitive strategy.^2-4 The European Mycotic Aneurysm Study confirmed that EVAR can provide initial stabilization; however, late infection-related complications and recurrent sac perfusion remain significant concerns.³ Long-term follow-up indicates that discontinuation of antibiotics is associated with increased infection-related mortality, underscoring the need for prolonged therapy.³ Comparative studies suggest that, in carefully selected patients, outcomes may approximate those of open repair, although surgical excision is still recommended when technically feasible and the patient’s condition allows.⁵ A recent systematic review emphasized the heterogeneity of reported outcomes and the absence of consensus regarding optimal antibiotic duration, reflecting the ongoing challenges in managing infected aneurysms.⁶ These difficulties are particularly evident in dialysis patients, where both surgical and endovascular strategies may be constrained.

Our patient illustrates these therapeutic dilemmas. Frailty, porcelain aorta, and multiple comorbidities precluded open repair, while endovascular treatment was complicated by endoleak and persistent sac infection. Ultimately, prolonged antibiotic therapy and palliation remained the only realistic strategy. This case also underscores the hazards of unproven regenerative therapies, particularly stem cell injections performed in unregulated environments where infection control measures are unknown, as unexpected sources of bacteremia with potentially catastrophic consequences.